Carbamic acid esters as well as pest combatting agents and a method of making the same



Patented June 22, 1954 CARBAMIC ACID ESTERS AS WELL AS PEST COMBATTING AGENTS AND A METHOD OF MAKING THE SAME Hans Gysin, Alfred Margot, and Charles Simon, Basel, Switzerland, assignors to J. R. Geigy A. G., Basel, Switzerland, a Swiss firm No Drawing. Application December 9, 1952,

Serial No. 325,011

Claims priority, application Switzerland August 22, 1949 3 Claims. 1 This application is a continuation-in-part of our pending application Ser. No. 178,986 filed i August 11, 1950.

The present invention is concerned with 6- alkyl-z-pyronyl-( i)-dimethylcarbamates of the general formula:

wherein R represents a lower alkyl radical. These compounds are, among other things, excellently suited for combatting pests such as insects, especially flies, and other arthropods and also their stages of development.

The new compounds can be produced, for example, by the reaction of dimethyl carbamic acid chloride with 6-alky1-pyronones-(2.4) such as 6-methyl-, 6-ethyl, 6-n-pr0pyl-, 6-n-butyland 6-n-amyl-pyronone-(2.4). The reaction may be performed in the presence of acid binding agents or with salts of the enol form of the above named compounds.

The reaction may take place in the presence or absence of solvents such as benzene, acetone, dioxan, acetic acid ethyl ester. Acid binding agents which come into consideration are, e. g. potassium carbonate, sodium carbonate, sodium bicarbonate, sodium ethylate or tertiary organic bases such as triethylamine. In particular, the the alkali salts are suitable as enol salts.

The following example illustrates the production of the new compounds. Parts are always given as parts by weight and the temperatures are given in degrees centigrade.

Example 1 To convert into the potassium salt 12.6 parts of 6-methyl-pyronone-(2A) are dissolved in 100 parts of acetone, and the solution is heated to boiling with 8 parts of potassium carbonate so that 50 parts of acetone distill on. It is then allowed to cool to 50 when 50 parts of acetone and 12 parts of dimethyl carabamic acid chloride are added whereupon it is boiled for 24 hours. The reaction product is further worked up by separating the acetone solution from the inorganic salt constituents and any unchanged starting materials which may remain. G-methyl- 2-pyronyl-(4)-dimethyl carbamate of the formula:

O C ON(CH3)2 boils at -152 at 0.3 mm. pressure.

The following compounds can be produced in the same manner:

G-ethyl-Z-pyronyl- (4) -dimethylcarbamate, 6-n-propyl-2-pyronyl- (4) -dimethylcarbamate, G-n-butyl-Z-pyronyl- (4) -dimethylcarbamate, 6-n-amyl-2-pyronyl- (4) -dimethylcarbamate.

The biological properties of the new compounds are useful in various fields of pest control and the mode of employment depends entirely on the intended use. The active compounds can be used as such, e. g. in powder form, in the form of gas or mist or as smoke. For most purposes, however, it is more economical to combine them with suitable carriers and distributing agents. A number of such substances suitable for the usual forms of application such as dusting agents, spraying agents (suspensions), solutions, aerosols, emulsions and semi-solid preparations (ointments) are given below.

, As solid pulverulent carriers may be used, e. a. calcium carbonate, in the form of whiting or ground limestone, kaolin, bole, bentonite, talcum, powdered magnesia, kieselguhr, boric acid, tricalcium phosphate, and also powdered wood, powdered cork and other materials of a vegetable nature. By the addition of wetting agents and protective colloids the pulverulent preparations can be suspended in water and used as spraying agents. The active substance can be combined with the carrier for example by impregnating the carrier with solutions of the active ingredient, by mixing the molten active ingredient with the carriers, or by milling the components together.

Solutions (for spraying) in high boiling carrier solvents such as kerosene and similar mineral oil fractions, in methyl naphthalenes, xylenes, etc. are best suited for direct spraying of objects. They can also be used for impregnating wood. Solutions in lower boiling solvents such as trichlorethylene, tetrachlorethane, ethylene chloride are most suitable for spreading the active ingredient in the form of a mist. The latter solvents, and also, for example, benzine, xylene and chlorobenzene are also suitable for the impregnation of textiles. The active substances are soluble in water to some extent. Water,

3 therefore, if required with the addition of solvents, also comes into consideration as a carriersolvent and also water soluble organic solvents such as alcohol or acetone.

Fluoro-trichloromethane and difluoro-dichloromethane are examples of solvents and propelling agents for aerosols.

As emulsifying agents there come into consideration those of a cation-active nature such as quaternary ammonium compounds, anion-active agents such as soap, soft soap, resin soap, aliphatic monoesters of sulphuric acid and aliphatic aromatic sulphonic acids, and also non-ionogenic emulsifying agents such as higher molecular ethylene oxide condensation products. They are mixed to an emulsifiable concentration with the active ingredient with or without the addition of suitable solvents such as e. g. acetone, alcohols, cyclohexanone, benzene, toluene, xylene, tetrahydronaphthalene, alkylated naphthalenes, phthalic acid esters, mineral and vegetable oils, resins, and, if desired, water.

Petroleum jelly and other ointment bases in which the active ingredient can be incorporated are examples of semi-solid distributing agents.

The active ingredients can also be used together with attractives or lures to form a bait, such as, e. g. sugar for example in the form of dusting agents with sugar as the main carrier, or spraying agents or in the form of fiy-papers.

The various forms of application can generally be adapted to the intended use by the addition of substances which improve the distribution, the adhesive properties and resistance to rain on the treated surface, such as, e. g. fatty acids, resins, wetting agents, glue, casein or alginates. The biological activity can also be increased by the addition of substances with bactericidal, fungicidal or also insecticidal properties.

As bactericidal substances that can be added come into consideration, e. g. chlorinated phenols and quaternary ammonium compounds; suitable fungicidal compounds include e. g. sulphur in its various forms of application, such as lime-sulphur liquid, copper compounds such as copper oxychloride or Bordeaux liquid, and fluorides. As examples of further insecticidal compounds may be named: synthetic products like 1.1-bis- (p-chlorophenyl) -2.2.2-trichlorethane, v hexachlorocyclohexane, p-nitropheny1-diethyl-thiophosphate, tetra-ethyl-pyrophosphate, chlorinated camphene, 1.2.4.55.7-8.8-octachloro-4.7- methano-3a.4.7.7a-tetrahydroindane and 5.5-dimethyl dihydroresorcinol dimethyl carbamate. Pyrethrin and rotenone are suitable vegetable products.

Example 2.Sprin7cling agent (spray) (a) 2 parts of active ingredient, e. g. G-methyl- 2-pyronyl-(4)-dimethyl carbamate are dissolved in 10 parts of xylene and 88 parts of kerosene.

(b) 2 parts of active ingredient, e. g. S-methyl- 2-pyronyl-(4) -dimethy1 carbamate and 3 parts of 1.1-bis- (p-chlorophenyl) -2.2.2-trichlorethane are dissolved in 10 parts of xylene or another mutual solvent and parts of kerosene.

Both solutions are excellently suited for combatting fiies in the household and also in storerooms and slaughterhouses.

Example 3.Fumigating agent (a) 20 parts of active ingredient, e. g. 6- methyl-2-pyrony1-(4)dimethyl carbamate are mixed with 61 parts of sawdust which has previously been impregnated with 18.4 parts of potassium nitrate. The mass is shaped into tablet form under pressure.

(17) 50 parts of active ingredient, e. g. 6-methyl- 2-pyronyl-(4)-dimethyl carbamate, 22 parts of sugar, 12 parts of potassium chlorate, 2.4 parts of potassium nitrate and 13.6 parts of sawdust are ground and thoroughly mixed together. The mass is put into boxes and it is set alight by either a wick or a fuse.

The insecticidal smoke formed by burning the tablets or the boxed fumigating mass is specially suitable for combatting insects in closed spaces.

Example 4.Gas

CH3 O-C ON CHa HO OH at to wherein R represents a lower alkyl radical.

2. A pest combatting agent comprising as an active ingredient a compound of the general formula:

wherein R represents a lower alkyl radical.

3. As new chemical compound, the S-methyl- 2-pyronyl-(4) -dimetl1yl carbamate.

No references cited. 

1. AS NEW CHEMICAL COMPOUNDS, THE DIMETHYL CARBAMATES OF THE GENERAL FORMULA: 